scholarly journals Sensitivity and protein turnover response to glucocorticoids are different in skeletal muscle from adult and old rats. Lack of regulation of the ubiquitin-proteasome proteolytic pathway in aging.

1995 ◽  
Vol 96 (5) ◽  
pp. 2113-2119 ◽  
Author(s):  
D Dardevet ◽  
C Sornet ◽  
D Taillandier ◽  
I Savary ◽  
D Attaix ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Turnover ◽  
Proteolytic Pathway ◽  
Ubiquitin Proteasome ◽  
Old Rats

Burn injury upregulates the activity and gene expression of the 20 S proteasome in rat skeletal muscle

2000 ◽  
Vol 99 (3) ◽  
pp. 181-187 ◽  
Author(s):  
Cheng-Hui FANG ◽  
Bing-Guo LI ◽  
David R. FISCHER ◽  
Jing Jing WANG ◽  
Herbert A. RUNNELS ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Burn Injury ◽  
Catalytic Core ◽  
Peptide Substrates ◽  
Protein Substrates ◽  
Proteolytic Pathway ◽  
Proteasome Subunits ◽  
Ubiquitin Proteasome ◽  
Dependent Protein ◽  
Increased Activity

There is evidence that burn injury stimulates ubiquitin–proteasome-dependent protein breakdown in skeletal muscle. In this proteolytic pathway, protein substrates are conjugated to multiple molecules of ubiquitin, whereafter they are recognized, unfolded and degraded by the multicatalytic 26 S protease complex. The 20 S proteasome is the catalytic core of the 26 S protease complex. The influence of burn injury on the expression and activity of the 20 S proteasome has not been reported. We tested the hypothesis that burn injury increases 20 S proteasome activity and the expression of mRNA for the 20 S proteasome subunits RC3 and RC7. Proteolytic activity of isolated 20 S proteasomes, assessed as activity against fluorogenic peptide substrates, was increased in extensor digitorum longus muscles from burned rats. Northern-blot analysis revealed that the expression of mRNA for RC3 and RC7 was increased by 100% and 80% respectively following burn injury. Increased activity and expression of the 20 S proteasome in muscles from burned rats support the concept that burn-induced muscle cachexia is at least, in part, regulated by the ubiquitin–proteasome proteolytic pathway.

scholarly journals Insights into the Abnormalities of Chronic Renal Disease Attributed to Malnutrition

2002 ◽  
Vol 13 (suppl 1) ◽  
pp. S22-S27
Author(s):  
William E. Mitch
Keyword(s):  
Lean Body Mass ◽  
Body Mass ◽  
Protein Turnover ◽  
Serum Proteins ◽  
Chronic Renal Disease ◽  
Protein Levels ◽  
Proteolytic Pathway ◽  
Ubiquitin Proteasome ◽  
Proteasome Pathway ◽  
Biochemical Mechanisms

ABSTRACT. Low values of serum proteins and loss of lean body mass are commonly found in patients with chronic renal insufficiency (CRI) and especially in dialysis patients. These abnormalities have been attributed to malnutrition (i.e., an inadequate diet), but available evidence indicates that this is not the principal cause. In contrast, there is persuasive evidence that secondary factors associated with the CRI condition cause abnormalities in protein turnover and ultimately result in low serum protein levels and loss of lean body mass. Recent reports have identified some factors that could interfere with the control of protein turnover in CRI patients, including acidosis, inflammation, and/or resistance to anabolic hormones. Each of these stimulates protein breakdown in muscle and activates a common proteolytic pathway, the ubiquitin-proteasome pathway. Moreover, acidosis or inflammation suppress hepatic albumin synthesis. Understanding the biochemical mechanisms that regulate the ubiquitin-proteasome and other catabolic pathways are required to identify new strategies for preventing protein deficits that are associated with CRI.

Aerobic exercise training upregulates skeletal muscle calpain and ubiquitin-proteasome systems in healthy mice

2012 ◽  
Vol 112 (11) ◽  
pp. 1839-1846 ◽  
Author(s):  
Telma F. Cunha ◽  
Jose B. N. Moreira ◽  
Nathalie A. Paixão ◽  
Juliane C. Campos ◽  
Alex W. A. Monteiro ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Aerobic Exercise ◽  
Protein Turnover ◽  
Muscle Protein ◽  
26S Proteasome ◽  
Aerobic Exercise Training ◽  
Skeletal Muscle Protein ◽  
Ubiquitin Proteasome ◽  
Calpain System

Aerobic exercise training (AET) is an important mechanical stimulus that modulates skeletal muscle protein turnover, leading to structural rearrangement. Since the ubiquitin-proteasome system (UPS) and calpain system are major proteolytic pathways involved in protein turnover, we aimed to investigate the effects of intensity-controlled AET on the skeletal muscle UPS and calpain system and their association to training-induced structural adaptations. Long-lasting effects of AET were studied in C57BL/6J mice after 2 or 8 wk of AET. Plantaris cross-sectional area (CSA) and capillarization were assessed by myosin ATPase staining. mRNA and protein expression levels of main components of the UPS and calpain system were evaluated in plantaris by real-time PCR and Western immunoblotting, respectively. No proteolytic system activation was observed after 2 wk of AET. Eight weeks of AET resulted in improved running capacity, plantaris capillarization, and CSA. Muscle RING finger-1 mRNA expression was increased in 8-wk-trained mice. Accordingly, elevated 26S proteasome activity was observed in the 8-wk-trained group, without accumulation of ubiquitinated or carbonylated proteins. In addition, calpain abundance was increased by 8 wk of AET, whereas no difference was observed in its endogenous inhibitor calpastatin. Taken together, our findings indicate that skeletal muscle enhancements, as evidenced by increased running capacity, plantaris capillarization, and CSA, occurred in spite of the upregulated UPS and calpain system, suggesting that overactivation of skeletal muscle proteolytic systems is not restricted to atrophying states. Our data provide evidence for the contribution of the UPS and calpain system to metabolic turnover of myofibrillar proteins and skeletal muscle adaptations to AET.

IGF-I has no effect on postexercise suppression of the ubiquitin-proteasome system in rat skeletal muscle

2002 ◽  
Vol 92 (6) ◽  
pp. 2277-2284 ◽  
Author(s):  
Anthony J. Kee ◽  
Alan J. Taylor ◽  
Anthony R. Carlsson ◽  
Andre Sevette ◽  
Ross C. Smith ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Endurance Exercise ◽  
Protein Turnover ◽  
Muscle Protein ◽  
Male Rats ◽  
Ubiquitin Proteasome Pathway ◽  
Muscle Protein Turnover ◽  
Igf I ◽  
Ubiquitin Proteasome ◽  
Proteasome Pathway

Both exercise and insulin-like growth factor I (IGF-I) are known to have major hypertrophic effects in skeletal muscle; however, the interactive effect of exogenous IGF-I and exercise on muscle protein turnover or the ubiquitin-proteasome pathway has not been reported. In the present study, we have examined the interaction between endurance exercise training and IGF-I treatment on muscle protein turnover and the ubiquitin-proteasome pathway in the postexercise period. Adult male rats (270–280 g) were randomized to receive 5 consecutive days of progressive treadmill exercise and/or IGF-I treatment (1 mg · kg body wt−1 · day−1). Twenty-four hours after the last bout of exercise, the rate of protein breakdown in incubated muscles was significantly reduced compared with that in unexercised rats. This was associated with a significant reduction in the chymotrypsin-like activity of the proteasome and the rate of ubiquitin-proteasome-dependent casein hydrolysis in muscle extracts from exercised compared with unexercised rats. In contrast, the muscle expression of the 20S proteasome subunit β-1, ubiquitin, and the 14-kDa E2 ubiquitin-conjugating enzyme was not altered by exercise or IGF-I treatment 24 h postexercise. Exercise had no effect on the rates of total mixed muscle protein synthesis in incubated muscles 24 h postexercise. IGF-I treatment had no effect on muscle weights or the rates of protein turnover 24 h after endurance exercise. These results suggest that a suppression of the ubiquitin-proteasome proteolytic pathway after endurance exercise may contribute to the acute postexercise net protein gain.

Activity and expression of the 20S proteasome are increased in skeletal muscle during sepsis

1999 ◽  
Vol 277 (2) ◽  
pp. R434-R440 ◽  
Author(s):  
Scott C. Hobler ◽  
Arthur Williams ◽  
David Fischer ◽  
Jing Jing Wang ◽  
Xiaoyan Sun ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Proteolytic Activity ◽  
Blot Analysis ◽  
20S Proteasome ◽  
Catalytic Core ◽  
Proteolytic Pathway ◽  
Ubiquitin Proteasome ◽  
Dependent Protein ◽  
26S Protease

Recent studies suggest that sepsis stimulates ubiquitin-dependent protein breakdown in skeletal muscle. In this proteolytic pathway, ubiquitinated proteins are recognized, unfolded, and degraded by the multicatalytic 26S protease complex. The 20S proteasome is the catalytic core of the 26S protease complex. The role of the 20S proteasome in the regulation of sepsis-induced muscle proteolysis is not known. We tested the hypothesis that sepsis increases 20S proteasome activity and the expression of mRNA for various subunits of this complex. Proteolytic activity of isolated 20S proteasomes, assessed as activity against fluorogenic peptide substrates, was increased in extensor digitorum longus muscles from septic rats. The proteolytic activity was inhibited by specific proteasome blockers. Northern blot analysis revealed an approximately twofold increase in the relative abundance of mRNA for the 20S α-subunits RC3 and RC9 and the β-subunit RC7. However, Western blot analysis did not show any difference in RC9 protein content between sham-operated and septic rats. The increased activity and expression of the 20S proteasome in muscles from septic rats lend further support for a role of the ubiquitin-proteasome-pathway in the regulation of sepsis-induced muscle proteolysis.

scholarly journals Sepsis is associated with increased mRNAs of the ubiquitin-proteasome proteolytic pathway in human skeletal muscle.

1997 ◽  
Vol 99 (2) ◽  
pp. 163-168 ◽  
Author(s):  
G Tiao ◽  
S Hobler ◽  
J J Wang ◽  
T A Meyer ◽  
F A Luchette ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Human Skeletal Muscle ◽  
Proteolytic Pathway ◽  
Ubiquitin Proteasome
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